2021年云南省3次中强地震前后热红外异常特征分析

Analysis of thermal infrared brightness temperature anomaly characteristics before and after three moderate earthquakes in Yunnan area,2021

基于中国静止气象卫星FY-2G热红外观测数据,采用连续小波变换和相对功率谱方法,对2021年云南省3次中强地震,即漾濞M_(S)6.4地震、双柏M_(S)5.1地震和盈江M_(S)5.0地震发生前后的地表亮温异常时空演化特征进行分析。结果表明:震前均存在显著的热红外亮温异常现象,其异常首先出现在区域主要活动断裂一端,沿断裂带扩展,异常面积和相对功率谱幅度均逐渐增强;之后迅速减弱,在衰减过程中发震,震中多位于异常增温区边缘或附近。分析认为,3次地震热红外亮温异常的可能原因是,区域应力累积致使岩层破裂,地壳深源气体和流体与周围岩层相互作用,造成地表产生增温效应。

Based on the daily thermal infrared observations from the Chinese geostationary meteorological satellite FY-2G,we analyzed the spatio-temporal evolution characteristics of brightness temperature anomalies before and after three moderate earthquakes in Yunnan area,2021,namely the Yangbi M_(S) 6.4 earthquake,the Shuangbai M_(S) 5.1 earthquake,and the Yingjiang M_(S) 5.0 earthquake,by using continuous wavelet transform and relative power spectrum.The results showed that there were obvious brightness temperature anomalies before the earthquakes,which firstly appeared at one end of the main active fault in the region and then spread gradually along the fault.The anomalous areas and relative power spectrum amplitude increased gradually,and then rapidly weakened after peak.The earthquakes occurred during the attenuation process.The epicenters were located at the edge of or close to anomalous regions.The paper concluded that apossible reason for the three brightness temperature anomalies was that regional stress accumulation resulted in rock rupture and the interaction of deep crustal gas and fluid with surrounding rock caused surface warming.